Post on 30-Jan-2021
Memorandum
999 West Main Street
Suite 1200
Boise, ID 83702
United States
T +1.208.345.5310
www.jacobs.com
BI0928181421BOI
Subject Expanded Borrow Source Desktop Study – Pine Creek Dam
Project Name Pine Creek Reservoir
Attention Chris Hyland, Walla Walla Watershed Management Partnership (WWWMP)
From Greg Warren and Jaco Esterhuizen, Jacobs Engineering Group, Inc. (Jacobs)
Date December 10, 2019
Copies to Brian Wolcott, Walla Walla Basin Watershed Council (WWBWC)
Jacobs’ previous technical memoranda described the geological setting and the potential for active faults below the dam. Given the risk of active faulting, a concrete dam is not considered a suitable dam type for the site. Acceptable dam types would include an earthen dam or an earth core rockfill dam constructed with conservative geometrical dimensions and suitable material to accommodate movement. For the core of a dam, which may be subject to fault offset, the resistance to concentrated leakage is the most important factor in the decision. Sherard (1974) classified core material based on its resistance to concentrated leaks, as follows:
1) Very good materials: Very well-graded coarse mixtures of sand, gravel, and fines
2) Good materials: (i) Well-graded mixtures of sand, gravel, and clayey fines; (ii) highly plastic tough clay (CH) with plasticity index greater than 20
3) Fair materials: (i) Fairly well-graded gravelly, medium to coarse sand with cohesionless fines; (ii) clay of medium plasticity (CL) with plasticity index greater than 12; (iii) coarse mixtures of sand, gravel, and fines
4) Very poor materials: (i) fine, uniform, cohesionless silty sand; (ii) silt from medium plasticity to cohesionless (ML) (plasticity index less than 10) because these materials are highly erodible
If borrow material for the dam core must be designed for a dam with a potentially active fault in the foundation (with acceptable estimated rupture movement), it is imperative that a very good or good borrow source be identified. Fair materials should only be considered if it can be concluded with a high degree of certainty that there is no active fault in the dam foundation. Under no circumstances should very poor materials as defined herein be considered for the dam.
During previous studies, including a review of geological maps, published geological and geotechnical reports, a field investigation, and laboratory testing, it has been determined that material such as plastic clay or well-graded silt/sand/gravel mixtures, suitable to construct a large dam on a potentially active fault, is not available near the site (Jacobs 2019). Nearby existing gravel and sand pits were observed during the previous search for local sources, but the local gravel pits were all situated on floodplains where a very shallow water table was present, which would limit large-scale development.
Because of these constraints, Jacobs conducted a limited desktop search for suitable materials in a larger geographic area, to evaluate whether more distant sources could be used
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Expanded Borrow Source Desktop Study
Pine Creek Dam
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economically. This desktop study focused on available information about existing material sources; including sand/gravel pits, sand/gravel deposits that have not been developed, and potential clay material in the Ringold Formation.
1. Expanded Desktop Study
2.1 Database and Literature search on Existing and Potential Sources
The expanded desktop study began with a database search for active and inactive material sources within an approximate 40-mile geographic radius. This search included searches for gravel/sand pits, and clay sources. No existing active clay sources were found.
Attachment 1 is a map that shows locations of active and inactive material sources and types in both Oregon and Washington within the 40-mile radius. Table 1 provide details of the available information about these sources and material types. Note, complete information about each material source is not readily available and would require onsite reconnaissance. If the listed sand/gravel pits contain materials with sufficient fines that are sufficiently well-graded, they could provide Fair to Good dam core materials (as described). Additional information, such as laboratory test results and field borings, would be needed to confirm the gradations and the quantities available. Many of the originally identified sand/gravel pits are actually rock quarries used to produce crushed rock and aggregate and would therefore not be useful for large-scale fines/sand/gravel production.
The haul distances to these sources are up to 40 miles. The haul times could be up to approximately 1 hour each way, based on local speed limits and road conditions. In Umatilla County, Oregon, numerous sand and gravel sources have been developed in Missoula Flood gravels along the Columbia River. The closest existing sources to Pine Creek in Umatilla County are near Hat Rock State Park, approximately 40 miles from the site via Highway 730 through Wallula Gap. However, a large, unmined gravel deposit is identified on the geological map closer to the south side of Wallula Gap, approximately 35 miles (Walker 1973).
2.2 Ringold Formation Evaluation
As previous documentation mentioned, one potential geological resource is the Ringold Formation. This geological unit is mapped beneath Eureka Flats, northwest of the proposed dam site, on the southeastern side of the Snake River.
This formation consists of a heterogeneous sequence of gravel, sand, silt, and clay. It is described by Newcomb (1958) and Lindsey (1996) as having a stratigraphic thickness of about 620 feet of horizontally bedded continental sediments from about 340 to 960 feet in altitude. The uppermost 505 feet of the type section, between 455 and 960 feet in altitude, is composed of silt, sand, gravel, clay, and volcanic ash. Geological sections in some areas indicate tan, greenish, brown, clay that is described as “plastic, silty, and massive” (Newcomb 1958) between altitudes of 465 and 650 feet in elevation.
The lower part, extending upward from river level at 340 feet to the base of the lacustrine deposits, at 455 feet, is composed of a weakly indurated conglomerate member that was deposited by river currents. The lowest lacustrine composite of the Ringold is commonly called the "blue clay" section, and lies below the conglomerate and below river level, where it rests
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Expanded Borrow Source Desktop Study
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upon the basalt bedrock. The blue clay is likely too deep to be exploited, as it is below Columbia River level.
No existing borrow or commercial material sources, such as gravel pits, were identified in the Ringold Formation in the study area. Table 2 describes the lithology from selected nearby well drillers’ logs (Ecology 2019). The lithological descriptions are not always accurate, and are typically only used as a guideline to steer further exploration and research. Attachment 2 is a map that shows the general location of the wells researched, very crude outlines of potential clay sources, and areas of sand and gravel. In general, these sources are between 30 and 40 miles from the site, based on existing roads. The haul times are anticipated to be between 45 minutes and 1 hour, depending on speed limits and local road conditions.
2. Conclusions
Numerous existing sand and gravel pits were identified within a 40-mile radius of the proposed Pine Creek Dam site(s). These indicate large quantities of sand and gravel have been historically mined and additional resources are likely available. These sand/gravel pits, if they contain sufficient fines (greater than 30 percent, for example) and are sufficiently well-graded, could provide Fair to Good core material for a dam. Depending on additional fault mapping, data, and research, Fair to Good core material (such as sand/gravel mixtures with sufficient fines) may be suitable for constructing a dam core, provided there is a relatively low risk of active faulting in the dam foundation. Additional information would be needed about these sources to confirm their suitability and quantities, such as laboratory test results including gradations and field borings.
In addition, well drillers’ logs from the Ringold Formation in the Eureka Flats area indicate that thick, near-surface clay deposits may be present within approximately 35 miles. If it is determined that the risk of an active fault beneath the proposed dam is relatively high, but still acceptable, an enhanced search for clay that would qualify as Good core material should be conducted in the area. A highly plastic clay (CH) with plasticity index greater than 20 would qualify as Good core material.
3. References
Duerr, T. C. 2010. Directory of Washington State Surface Mining Reclamation Sites – 2010. Washington
Division of Geology and Earth Resources Open File Report 2010-7.
Jacobs Engineering Group Inc. (Jacobs). 2019 Evaluation of Potential Active Fault in Dam Foundation.
Technical Memorandum. Prepared for Walla Walla Watershed Management Partnership.
Lindsey, K. A. 1996. The Miocene to Pliocene Ringold Formation and Associated Deposits of the
Ancestral Columbia River System, South-central Washington and North-central Oregon, Washington
Division of Geology and Earth Resources Open File Report 96-8.
Newcomb, R. C. 1958. “Ringold Formation of Pleistocene Age in Type Locality, the White Bluffs,
Washington.” American Journal of Science. Vol. 256. pp. 328-340.
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Schlicker, H. G., R.A. Schmuck, and J.G. Gray. 1976. Rock Material Resources of Umatilla County,
Oregon Department of Geology and Mineral Industries. Short Paper No. 26.
Sherard J.L., L.S. Cluff, and C.R. Allen. 1974. “Potentially active faults in dam foundations.”
Géotechnique. Vol. 24. No.3. pp. 367-428.
Walker, G. W. 1973. Reconnaissance Geologic Map of the Pendleton Quadrangle, Oregon and Washington. U. S. Geological Survey Miscellaneous Geologic Investigations Map I-727. Scale 1:250,000.
Washington Department of Ecology (Ecology). 2019. Well Log Search. Available at:
https://fortress.wa.gov/ecy/wellconstruction/map/WCLSWebMap/WellConstructionMapSearch.aspx
Accessed 12/4/2019.
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TABLE 1 DATABASE AND GEOLOGIC MAP SEARCH
DOGAMI Minerals
COMMODITY SITE NAME OWNER LAT LONG MAP UNIT
sand and gravel gravel pit S.D. Spencer & Sons Co 45.977311 -118.384943 Alluvium
sand and gravel Eastside Pit Ready Mix sand and gravel, Inc 45.961461 -118.382414 Alluvium
sand and gravel Eastside Pit Umatilla Co Road Department 45.961461 -118.382414 Alluvium
sand and gravel gravel pit unnamed or NA 45.95096 -118.419236 Alluvium
sand and gravel gravel pit unnamed or NA 45.957636 -118.434689 Alluvium
sand and gravel gravel pit unnamed or NA 45.908466 -119.159454 Flood deposits
WA Surface Mine Sites
Sand and Gravel
WALLA WALLA GRAVEL & ROCK 46.136341 -118.24354 Basalt
Undeveloped
sand and gravel n/a
Undeveloped; large gravel deposit
identified on Geologic map. 45.951661 -119.040339 Flood deposits
WA Nonmetallic Minerals - old historical inactive sources
Common clays and shales Kennewick (not active) Silty alluvial clay
Used in making common brick by Columbia
Clay Co. about 1910
Common clays and shales Dayton (not active)
Palouse Formation
clay. Brick yard formerly used this material.
Common clays and shales Walla Walla (not active) Recent alluvium
A good grade of brick and tile formerly made
from this material at brick plant near the site.
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TABLE 2 WELL LOGS AND LITHOLOGY
Well Name Lat Long Formation Depth/Lithology Est. Haul Distance (mi)
KZH Farms 46.2987 -118.636 Ringold 0 - 3 overburden 32
3 - 220 Gray clay
Willits 46.2963 -118.6827 Ringold 0 - 3 topsoil 35
3 - 40 Silty sand gravel
cobble
Provencher 46.2308 -118.7246 Ringold 0 - 38 Brown sandy clay 35
38 - 45 light clay and
boulders
Alpha 6 46.1992 -118.7404 Ringold 1 - 10 silty sand 26
10 - 35 brown clay
Grand View farms 46.1455 -118.8082 Ringold 0 - 31 sandy brown clay 28
31 - 34 brown claystone
34 - 86 brown clay
Kolke 46.1991 -118.8662 Ringold 0 - 89 brown silty clay 36
89 - 108 gravel
Davies 46.1924 -118.7591 Ringold 3 - 29 Till? Silty sand 36
29 - 67 blue sand
Hansen 46.3416 -118.6412 Ringold 1 - 3 topsoil 36
3 - 137 brown clay
Cowell 46.3494 -118.54893 Ringold 0 - 10 soil 36
10 - 90 sand - clay mix
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Mesa 46.352 -118.5303 Ringold 0 - 15 sand 36
15 - 29 clay
Notes:
1. Haul distances approximated; don't include local roads/farm roads.
2. Lithology derived from well drillers logs
UNK G:\WATER_RESOURCES\WREM\ZABROWSKI\WALLAWALLA\GIS\MAPFILES\WALLAWALLA_BORROWSOURCES_UPDATE.MXD RZ068062 12/10/2019 3:08:05 PM
VICINITY MAP
Notes:1. Refer to Table 1 for additional information on historic material sources.2. Well Driller's Logs used to interpret lithology of Ringold Formation. See Table 2.
Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics,CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS UserCommunity, Esri, HERE, Garmin, © OpenStreetMap contributors, andthe GIS user community
0 3 6 9 12Miles
Sources: Esri, HERE, Garmin,USGS, Intermap,INCREMENT P, NRCan, EsriJapan, METI, Esri China(Hong Kong), Esri Korea, Esri
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ATTACHMENT 1Potential Borrow SourcesExpanded Desktop Borrow Source StudyPine Creek Dam and Reservoir
Project Site
Large unmined gravel/sand deposit
LEGENDHistoric Clay SourceHistoric Sand & Gravel Source40 Mile Radius from Project SiteBureau of Indian AffairsBureau of Land ManagementBureau of ReclamationCorps of Engineers
Private
StateU.S. Fish and Wildlife ServiceU.S. Forest Service
gwarrenPolygon
gwarrenCalloutArea shown in Attachment 2: Well Logs in Ringold Formation
2019-12-10T17:19:33-0800Esterhuizen, Jaco INC00017366